Methods for recovering non-ferrous metals from dross are known to art. For example, the Canadian Patent 1,255,914 teaches a method for recovering non-ferrous metal from non-ferrous-metal containing dross. The method includes the steps of feeding the dross into a rotary furnace that has a refractory lining, directing a plasma burner into the furnace so as to heat the dross to a temperature above the melting point of the metal, rotating the furnace either continuously or intermittently, and removing the molten, separated metal from the solid dross residue.
It is also known to recover non-ferrous metals from dross and metal waste with the aid of oxy-fuel-burners while using a protective layer of salts. This layer may include sodium chloride (NaCl), potassium chloride (KCl) in roughly equal quantities with respect to weight, and may also contain a flux, for instance cryolite. The effect of the salt layer on the coalescence of aluminum droplets when treating aluminum dross is described, for instance, in the Second International Symposium; Recycling of metals and engineered materials, The minerals, metals and materials Society, 1990, pages 69-84, by Ray D. Petersen, entitled "Effect of salt flux additives on aluminum droplet coalescence". In an article entitled "Interfacial phenomena in molten aluminum and salt systems" published in the same reference, pages 85-103, Francis K. Ho and Yogesh Sahai describe the remelting of aluminum waste beneath a salt layer.